Fox and Blue Sky's RIO easily sailed into the #1 spot at the U.S. box office for the weekend of April 15-17, 2011. The Carnivale-themed animated feature scored $40 million.

Dimension Films' SCREAM 4 slashed into second with $19.3 million. The horror franchise flick has vfx from Prime Focus and Rez-Illusion.

Universal's HOP bounced into third after having taken the top spot for two weeks in a row. With vfx from Rhythm & Hues, the Easter Bunny comedy put another $11.2 million in its total nest of $82.6 million.

TriStar's SOUL SURFER floated into fourth again with $7.4 million. With vfx from Engine Room, the true-life shark attack drama has brought in $20 million in total.

Focus Features' HANNA slipped from second to fifth, earning $7.33 million. With vfx from Exozet Effects, Mr. X and Snow Business, the teen assassin tale has a cume of $23.3 million.

Warner Bros.' ARTHUR laughed into sixth, bringing in an additional $6.94 million. With vfx from Gravity, the comedy remake has earned $22.3 million to date.

FilmDistrict's INSIDIOUS crept into seventh, raising $6.86 million. With vfx from Fractured FX, the haunted house horror flick has total box office receipts of $36 million.

Summit's SOURCE CODE slipped one spot to eighth, making an additional $6.3 million. With vfx from Modus Fx, Moving Picture Company (MPC), Oblique FX and Rodeo FX, the sci-fi thriller has a cume of $37 million.